3-aryl-2-hydroxypropionic acid derivative III

ABSTRACT

A novel 3-aryl-2-hydroxypropionic acid derivative, a process and intermediate for its manufacture, pharmaceutical prepartions containing it and the use of the compound in clinical conditions associated with insulin resistance.

FIELD OF INVENTION

The present invention releates to a novel 3-aryl-2-hydroxypropionic acid derivative, to a process and intermediate for preparing such a compound, having the utility in clinical conditions associated with insulin resistance, to methods for its therapeutic use and to pharmaceutical compositions containing it.

BACKGROUND OF THE INVENTION

Insulin resistance, defined as reduced sensitivity to the actions of insulin in the whole body or individual tissues such as skeletal muscle, myocardium, fat and liver prevail in many individuals with or without diabetes mellitus. The insulin resistance syndrome, IRS, refers to a cluster of manifestations including insulin resistance with accompanying hyperinsulinemia, possibly non insulin dependent diabetes mellitus (NIDDM); arterial hypertension; central (visceral) obesity; dyslipidemia observed as deranged lipoprotein levels typically characterized by elevated VLDL (very low density lipoproteins) and reduced HDL (high density lipoproteins) concentrations and reduced fibrinolysis.

Recent epidemiological research has documented that individuals with insulin resistance run a greatly increased risk of cardiovascular morbidity and mortality, notably suffering from myocardial infarction and stroke. In non-insulin dependent diabetes mellitus these atherosclerosis related conditions cause up to 80% of all deaths.

In clinical medicine there is at present only limited awareness of the need to increase the insulin sensitivity in IRS and thus to correct the dyslipidemia which is considered to cause the accelerated progress of atherosclerosis.

Furthermore there is at present no pharmacotherapy available to adequately correct the metabolic derangements associated with IRS. To date, the treatment of NIDDM has been focused on correction of the deranged control of carbohydrate metabolism associated with the disease. Stimulation of endogenous insulin secretion by means of secretagogues, like sulphonylureas, and if necessary administration of exogenous insulin are methods frequently used to normalize blood sugar but that will, if anything, further enhance insulin resistance and will not correct the other manifestations of IRS or reduce cardiovascular morbidity and mortality. In addition such treatment involves a significant risk of hypoglycemia with associated complications.

Other therapeutic strategies have focused on aberrations in glucose metabolism or absorption, including biguanides, such as methformin, or glucosidase inhibitors, such as acarbose. Although these agents have been efficacious to a degree, their limited clinical effect is associated with side effects.

A novel therapeutic strategy involves the use of insulin sensitizing agents, such as the thiazolidinediones, which, at least in part, mediate their effects via an agonistic action on nuclear receptors. Ciglitazone is the prototype in this class. In animal models of IRS these compounds seem to correct insulin resistance and the associated hypertriglyceridaemia and hyperinsulinemia, as well as hyperglycemia in diabetes, by improving insulin sensitivity via an effect on lipid transport and handling, leading to enhanced insulin action in skeletal muscle, liver and adipose tissue.

Ciglitazone as well as later described thiazolidinediones in clinical development either have been discontinued reportedly due to unacceptable toxicity or show inadequate potency. Therefore there is a need for new and better compounds with insulin sensitizing properties.

PRIOR ART

Compounds of the formula

and certain derivatives thereof disclosed in U.S. Pat. No. 5,306,726 and WO 91/19702 are said to be useful as hypoglycemic and hypocholesterolemic agents, and in U.S. Pat. No. 5,232,945 said to be useful in the treatment of hypertension.

AU 650 429 discloses structurally related compounds, but claimed to have different properties: diuretic, antihypertensive, platelet anti-aggregating and anti-lipoxygenase properties.

EP 139 421 discloses compounds having the ability to lower blood lipid and blood sugar levels. Among these compounds is troglitazone, a compound that has reached the market for treatment of NIDDM or decreased glucose tolerance.

DESCRIPTION OF THE INVENTION

It has now surprisingly been found that the novel compound 3-{4-[2-(4-tert-Butoxycarbonylaminophenyl)ethoxy]phenyl}-(S)-2-ethoxy propanoic acid having the formula I

is effective in conditions associated with insulin resistance.

The invention also relates to pharmaceutically acceptable salts, solvates, such as hydrates, and crystalline forms of the compound of the formula I.

In the present specification the expression “pharmaceutically acceptable salts” is intended to define but is not limited to such salts as the alkali metal salts (e.g. sodium, lithium and potassium), alkaline earth metal salts (e.g. calcium, barium and magnesium), aluminum, zinc and bismuth salts, ammonium salts, salts with basic amino acids, such as arginine, lysine, and salts with organic amines such as ethanolamine, ethylenediamine, triethanoleamine, benzylphenethylamine, diethylamine, tromethamine, benzathine, chloroprocaine, choline, meglumine, procaine, clemizole and piperazine.

Throughout the specification and the appended claims, a given chemical formula or name shall encompass all pharmaceutically acceptable salts thereof, crystalline forms and solvates thereof such as for instance hydrates.

Methods of Preparation

The compound of the invention may be prepared as outlined below according to any of methods A-H. However, the invention is not limited to these methods, the compound may also be prepared as described for structurally related compounds in the prior art.

A. The compound of the formula I of the invention can be prepared by converting a compound of formula II

wherein A is —OR^(p), wherein R^(p) is a protective group, e.g. ethyl, or A is a chiral auxiliary group, such as a chiral amine, e.g. (R)-phenylglycinol, a chiral alcohol, such as menthol or a chiral oxazolidinone, such as (S)-4-benzyl-2-oxazolidinone. The convertion can be performed as a hydrolysis which can be either acidic or basic and performed according to standard methods known to anyone skilled in the art or as described in the experimental part.

B. The compound of the formula I or the formula II wherein A is a chiral auxiliary group or —OR^(p) and R^(p) is as defined above, can be prepared by reacting a compound of the formula III

wherein X is —OH or a leaving group such as a sulfonate or a halogen, with a compound of the formula IV

wherein Q is H and A is a chiral auxiliary group, —OH or —OR^(p), and R^(p) is as defined above. The reaction can be performed either by an alkylation reaction or a Mitsunobu reaction.

In an alkylation reaction the leaving group X can be a sulfonate such as mesylate, nosylate, tosylate, or a halogen, such as bromine or iodine. The compounds of formula III and IV, in approximately equimolar amounts or with an excess of either compound, are heated to reflux temperature in an inert solvent, such as isopropanol or acetonitrile, in the presence of a base, such as potassium carbonate or cesium carbonate.

The mixture is refluxed for the necessary time, typically between 0.5 h to 24 h, the work-up procedure usually includes filtration, for removal of solid salt, evaporation, neutralization (when A=—OH) and extraction with water and an organic solvent such as dichloromethane, ethyl acetate, or diethyl ether. The crude product is purified if desired e.g. by recrystallization or by standard chromatographic methods.

The Mitsunobu reaction can be carried out according to standard methods or as described in for example Tsunoda T., Yamamiaya Y., Ito S., Tetrahedron Letters, 34, 1639-1642 (1993) or O. Mitsunobu, Synthesis, 1981, p.1. When using a Mitsunobu reaction A can not be —OH.

In a typical Mitsunobu reaction a compound of formula III, wherein the group X is a hydroxyl group, and a compound of formula IV are mixed, in approximately equimolar amounts or with an excess of either compound, in an inert solvent, such as chloroform, dichloromethane, or tetrahydrofran. A slight molar excess, 1-4 equivalents, of an azodicarboxylate, such as DEAD or ADDP and a phosphine (14 equivalents), such as tributylphosphine or triphenylphosphine are added and the reaction is stirred at a temperature high enough—for example room temperature—and a time long enough (1-24 hours) to obtain product, which can be worked up with standard literature methods and if desired purified, e.g. by standard chromatographic methods.

The compound of formula III can be prepared by standard procedures known to anyone skilled in the art, from commercially available staring materials or as described in the experimental section.

The compound of formula IV wherein Q is H and A is a chiral auxiliary group, —OH or —OR^(p), wherein R^(p) is as defined above, can be prepared as described below in the experimental part, or by converting a compound of formula IV

wherein Q is R^(q), wherein R^(q) is a protective group, e.g. benzyl, and A is a chiral auxiliary group, —OH or —OR^(p), wherein R^(p) is as defined above.

C. The compound of formula II, wherein A is a chiral auxiliary group, and the compound of formula IV, wherein A is a chiral auxiliary group and Q is hydrogen or R^(q), wherein R^(q) is as defined above and, can be prepared by diastereoisomeric separation of the compound of the formula V

wherein A is a chiral auxiliary group, Q is hydrogen, —CH₂CH₂Ph-4-NHCOO^(t)Bu or R^(q), wherein R^(q) is as defined above. The separation of the diastereomers can be performed either by crystallization or by chromatography. The chromatographic separation can be performed as described in the experimental part.

The compound of formula V wherein A is a chiral auxiliary group, Q is hydrogen, —CH₂CH₂Ph-4-NHCOO^(t)Bu or R^(q), wherein R^(q) is as defined above, can be prepared by converting a compound of formula VI

wherein Q is hydrogen, —CH₂CH₂Ph-4-NHCOO^(t)Bu or R^(q) and R^(x) is hydrogen or R^(p), wherein R^(q) and R^(p) are as defined above, for example by reacting it with a chiral amine or a chiral alcohol.

The compound of formula V when A is a chiral amine can be prepared by reacting a compound of formula VI with a chiral amine such as (R)-phenyl glycinol for example in the presence of a peptide coupling system (e.g. EDC, DCC, HBTU, TBTU, PyBop or oxalylchloride in DMF), an appropriate base (e.g. pyridine, DMAP, TEA or DIPEA) and a suitable organic solvent (e.g. dichloromethane, acetonitrile or DMF) in accordance with methods well known to those skilled in the art or as described in the examples.

The compound of formula V when A is a chiral alcohol can be prepared in the same way using a chiral alcohol, such as menthol, instead of a chiral amine, or by the mixed-anhydride method with pivaloyl chloride and the lithium salt of the chiral alcohol.

The compound of formula V wherein A is a chiral auxiliary group and Q is hydrogen, —CH₂CH₂Ph-4-NHCOO^(t)Bu or R^(q), wherein R^(q) is as defined above, and the compound of formula VI, wherein Q is hydrogen, —CH₂CH₂Ph-4-NHCOO^(t)Bu or R^(q) and R^(x) is hydrogen or R^(p), wherein R^(q) and R^(p) are as defined above, can be prepared by reduction of a compound of formula VII

wherein A is a chiral auxiliary group, —OH, or —OR^(p), wherein R^(p) is as defined above and Q is hydrogen, —CH₂CH₂Ph-4-NHCOO^(t)Bu or R^(q), wherein R^(q) is as defined above, and if desired followed by removal of protecting groups.

The reduction of the olefin may be carried out using a wide variety of reducing methods known to reduce carbon-carbon double bonds, such as catalytic hydrogenation in the presence of an appropriate catalyst, or hydrogen transfer reagents such as diethyl-2,5-dimethyl-1,4-dihydropyridine-3,5-dicarboxylate.

The catalytic hydrogenation can be performed in alcohol, cellosolves, protic polar organic solvents, ethers, lower aliphatic acids, and particularly in methanol, ethanol, methoxyethanol, dimethylformamide, tetralydrofuran, dioxane, dimetoxyethane, ethyl acetate or acetic acid either used alone or in mixture. Examples of the catalysts used include palladium black, palladium on charcoal, platinum oxide or Wilkinson's catalyst. This reaction can be preformed at different temperatures and pressures depending on the reactivity of the aimed reaction.

In case of hydrogen transfer reaction with diethyl-2,5-dimethyl-1,4-dihydropyridine-3,5-dicarboxylate the reaction can be conducted by mixing equimolar amounts of reactants and warming the mixture to melting (140-250° C.) under inert atmosphere or under vacuum.

The compound of formula VII wherein A is a chiral auxiliary group, —OH, or —OR^(p), wherein R^(p) is as defined above and Q is hydrogen, —CH₂CH₂Ph-4-NHCOO^(t)Bu or R^(q), wherein R^(q) is as defined above, can be prepared by a condensation reaction, such as a Knoevenagel or Wittig type reaction, of a carbonyl compound of the formula VIII

wherein Q is hydrogen, —CH₂CH₂Ph-4-NHCOO^(t)Bu or R^(q), wherein R^(q) is as defined above, with a compound of the formula IX

in which formula A is a chiral auxiliary group, —OH, —OR^(p), wherein R^(p) is as defined above, or the formula X

in which A is a chiral auxiliary group, or —OR^(p), wherein R^(p) is as defined above, L¹═L²═L³ are phenyl or L¹═L² are Oalkyl and L³ is=O, and, if desired, followed by removal of protecting groups, by an arylation reaction as described in for example Cacchi S., Ciattini P. G., Morera E., Ortar G., Tetrthedron Letters, 28 (28) 1987, pp 3039-3042.

In the condensation step, approximately equimolar amounts of reactants are mixed in the presence of a base, to provide the olefin compound. This step may be carried out in the presence of an inert solvent or in the absence of a solvent at a temperature between −20° C. and the melting point for the mixture. It might be necessary to add a dehydrating agent in order to obtain the olefinic compound.

In a typical such reaction the compounds of formula VIII and formula IX are mixed in a solvent such as tetrahydrofuran. Anhydrous potassium tert-butoxide is slowly added at low temperature i.e. −20° C. The reaction is quenched with acetic acid. The crude product is isolated, redissolved in toluene and refluxed with p-toluenesulfonic acid in a Dean-Stark apparatus. The solution is cooled and the product is isolated and purified according to standard methods (see Groger T., Waldmann E., Monatsh Chem 89, 1958, p 370).

The condensation step could also be performed as a Wittig-type reaction (see for example Comprehensive Organic Synthesis vol. 1 p. 755-781 Pergamon Press) or as described in the experimental part.

In a typical such reaction, approximately equimolar amounts of reactants of formula VIII and formula X, are stirred in the presence of a base such as tetramethylguanidine or potassium carbonate in a 1-5 fold molar excess. This step may be carried out in the presence of an inert solvent such as dichloromethane or acetonitrile and at a suitable temperature (−10° C.+60° C.) for a sufficient time.

The compound of the formula VIII when Q is —CH₂CH₂Ph-4-NHCOO^(t)Bu can be prepared by coupling a compound of the formula III wherein X is —OH or a leaving group such as a sulfonate or a halogen, with a compound of the formula XI

When X is a leaving group such as a sulfonate or a halogen, the reaction may be performed as an alkylation reaction and when X is —OH, as a Mitsunobu reaction as described above.

D. The compound of formula I or formula II wherein A is —OR^(p) and R^(p) is as defined above and the compound of formula IV wherein A is —OH or —OR^(p) and Q is H or R^(q), wherein R^(p) and R^(q) are as defined above can be prepared by enantiomeric separation, such as chiral chromatography of the compound of the formula V

wherein A is —OH or —OR^(p), Q is H, —CH₂CH₂Ph-4-NHCOO^(t)Bu or R^(q) wherein R^(p) and R^(q) are as defined above.

E. The compound of the formula I or the formula II wherein A is a chiral auxiliary group, or —OR^(p), wherein R^(p) is as defined above, and the compound of formula IV wherein A is a chiral auxiliary group, —OH, or —OR^(p), wherein R^(p) is as defined above and Q is hydrogen or R^(q), wherein R^(q) is as defined above, can be prepared by asymmetric reduction of a compound of the formula VII

wherein A is a chiral auxiliary group, —OH, or —OR^(p), wherein R^(p) is as defined above and Q is hydrogen, —CH₂CH₂Ph-4-NHCOO^(t)Bu or R^(q), wherein R^(q) is as defined above. The asymmetric reduction can be carried out using a wide variety of reducing methods which are known to reduce carbon-carbon double bonds such as catalytic hydrogenation in the presence of an appropriate chiral catalyst such as Rh-BINAP or [Et-DuPHOS-Rh(COD)] or catalytic hydrogenation with an appropriate catalyst, such as palladium on charcoal using the chiral auxiliary group to induce the asymmetry.

The catalytic hydrogenation can be carried out in a wide variety of solvents, such as alcohol, cellosolves, protic polar organic solvents, ethers, lower aliphatic acids, and particularly in methanol, ethanol, methoxyethanol, dimethylformamide, tetrahydrofuran, dioxane, dimetoxyethane, ethyl acetate or acetic acid, either used alone or in a mixture. The reaction can proceed at different temperatures and pressures depending on the reactivity of the aimed reaction.

F. The compound of the formula I or the formula II, wherein A is a chiral auxiliary group, or —OR^(p), wherein R^(p) is as defined above, and the compound of formula IV wherein A is a chiral auxiliary group, —OH, or —OR^(p), wherein R^(p) is as defined above and Q is hydrogen or R^(q), wherein R^(q) is as defined above, can be prepared by converting a compound of the formula XII

wherein A is a chiral auxiliary group, —OH, or —OR^(p), wherein R^(p) is as defined above, and Q is hydrogen, —CH₂CH₂Ph-4-NHCOO^(t)Bu or R^(q), wherein R^(q) is as defined above, with the required stereochemistry, dependent on the reaction conditions used.

The reaction may be carried out as an alkylation reaction, using a variety of alkylating agents, such as ethyl halide or diethyl sulfate (see for example Benedict D. R., Bianchi T. A., Cate L. A., Synthesis (1979), pp. 428-429, Barluenga J., Alonso-Cires L., Campos P. J., Asensio G., Synthesis, 1983, p. 53-55, Bull Chem Soc Jpn, 1986, 59, 2481, S. Patai, The Chemistry of the Ether Linkage, Wiley-Interscience NY, 1967, 445-498 or Survey of Organic Synthesis vol 1, Wiley-Interscience 1970, NY, p. 285-328).

The compound of formula XII wherein A is a chiral auxiliary group, —OH, or —OR^(p), wherein R^(p) is as defined above, and Q is hydrogen, —CH₂CH₂Ph-4-NHCOO^(t)Bu or R^(q), wherein R^(q) is as defined above, can be prepared by asymmetric reduction of a compound of the formula XIII

wherein A is a chiral auxiliary group, —OH, or —OR^(p), wherein R^(p) is as defined above, and Q is hydrogen, —CH₂CH₂Ph-4-NHCOO^(t)Bu or R^(q), wherein R^(q) is as defined above.

The asymmetric reduction may be performed by using a wide variety of reducing methods which are known to reduce ketones enantioselectively (see Flynn G. A., Beight D. W., Tetrahedron Letters, 29(4), 1988, pp. 423-426).

The compound of formula XII wherein A is a chiral auxiliary group and Q is hydrogen, —CH₂CH₂Ph-4-NHCOO^(t)Bu or R^(q), wherein R^(q) is as defined above, may also be prepared by induced chiral reduction of a compound of formula XIII, wherein A is a chiral auxiliary group and Q is hydrogen, —CH₂CH₂Ph-4-NHCOO^(t)Bu or R^(q), wherein R^(q) is as defined above (see Xiang Y. B., Snow K., Belley M., J. Org. Chem., 1993, 58, pp 993-994).

The compound of formula XII, wherein A is a chiral auxiliary group, —OH or —OR^(p), wherein R^(p) is as defined above, and Q is hydrogen, —CH₂CH₂Ph-4-NHCOO^(t)Bu or R^(q), wherein R^(q) is as defined above, can be prepared by converting a compound of the formula XIV

wherein A is a chiral auxiliary group, —OH or —OR^(p), wherein R^(p) is as defined above, and Q is hydrogen, —CH₂CH₂Ph-4-NHCOO^(t)Bu or R^(q), wherein R^(q) is as defined above, with the required stereochemistry, dependent on the reaction conditions used ( see for example K. Koga, C. C. Wu and S. Yamada, Tetrahedron Letters, no. 25, 1971, p 2283-2286, Kunz H., Lerchen H-G., Tetredronjetters, 28 (17)1987, pp.1873-1876).

G. The compound of formula II, wherein A is a chiral auxiliary group, and the compound of formula IV wherein A is a chiral auxiliary group and Q is R^(q), wherein R^(q) is as defined above, can be prepared by reacting a compound of formula XV

wherein X is a leaving group, such as a halogen or a sulfonate, and Q is —CH₂CH₂Ph-4-NHCOO^(t)Bu or R^(q), wherein R^(q) is as defined above, with a compound of the formula IX

wherein A is a chiral auxiliary group.

In the alkylation step the compound of formula XV is reacted with a compound of formula IX in the presence of one or more bases such as potassium carbonate, triethylbenzylammonium chloride, sodium hydride, LDA, butyllithium or LHMDS in a reaction inert solvent such as acetonitrile, DMF or dichloromethane at a suitable temperature and time. The reaction can be carried out using standard methods known in the literature: (see for example Pearsson W. H., Cheng M. C., J. Org. Chem., 51 (19) 1986, 3746-3748, Myers A. G., Yang B. H., Gleason J. L., J. Am. Chem. Soc. 1994, 116, pp 9361-9362, Negrete G. R., Konopelski J. P., Tetrahedron Assymetry, 2, 2, pp. 105-108, 1991, Davies S. G., Sanganee H. J., Tetredron Assymetry, 6, 3, pp. 671-674, 1995, Hulin B., Newton L. S., Lewis D. M., Genereux P. E., Gibbs E. M., Clark D. A. J. Med.Chem. 39, 3897-3907 (1996) and Savignac M., Durand J-O, Genet J-P, Tetrahedron Assymetry, 5, 4, pp.717-722, 1994).

The compound of formula XV wherein X is a leaving group, such as a halogen or a sulfonate, and Q is —CH₂CH₂Ph-4-NHCOO^(t)Bu or R^(q), wherein R^(q) is as defined above, can be prepared from a compound of formula XVI

wherein Q is —CH₂CH₂Ph-4-NHCOO^(t)Bu or R^(q), wherein R^(q) is as defined above, using standard methods known to anyone skilled in the art.

The compound of formula XVI wherein Q is —CH₂CH₂Ph-4-NHCOO^(t)Bu or R^(q), wherein R^(q) is as defined above, can be prepared by reduction of a compound of formula VIII, wherein Q is —CH₂CH₂Ph-4-NHCOO^(t)Bu or R^(q), wherein R^(q) is as defined above, by standard methods known to anyone skilled in the art.

H. The compound of the invention of formula I and the compound of formula IV, wherein A is —OH and Q is hydrogen or R^(q), wherein R^(q) is as defined above, can be prepared by resolution of the racemate thereof and, if desired, followed by neutralization. The resolution can be performed by separative crystallization of a salt consisting of the racemate of, either the compound of the invention of formula I, or the compound of formula IV, and a chiral base, such as quinine, in an inert solvent such as ethyl acetate or toluene (see for example Duhamel P., Duhamel L., Danvy D., Plaquevent J. C., Giros B., Gros C., Schwartz J. C., Lecomte J. M., U.S. Pat. No 5,136,076, Stephani R., Cesare V., J. Chem. Ed., 10, 1997, p. 1226 and Yamamoto M., Hayashi M., Masaki M., Nohira H., Tetrahedron Assymetry, 2, 6, pp. 403-406, 1991).

The compounds of the invention may be isolated from their reaction mixtures using conventional techniques.

Persons skilled in the art will appreciate that, in order to obtain the compounds of the invention in an alternative and in some occasions, more convenient manner, the individual process steps mentioned hereinbefore may be performed in different order, and/or the individual reactions may be performed at different stages in the overall route (i.e. chemical transformations may be preformed upon different intermediates to those associated hereinbefore with a particular reaction).

In any of the preceeding methods of preparation A-H, where necessary, hydroxy, amino or other reactive groups may be protected using a protecting group, R^(p) or R^(q) as described in the standard text “Protective groups in Organic Synthesis”, 2^(nd) Edition (1991) by Greene and Wuts. The protecting group R^(p) or R^(q) may also be a resin, such as Wang resin or 2-chlorotrityl chloride resin. The protection and deprotection of functional groups may take place before or after any of the reaction steps described hereinbefore. Protecting groups may be removed in accordance to techniques which are well known to those skilled in the art.

The expression “inert solvent” refers to a solvent which does not react with the starting materials, reagents, intermediates or products in a manner which adversely affects the yield of the desired product.

Unless otherwise stated or indicated the term chiral auxiliary group denotes a chiral group, such as a chiral alcohol or amine, for instance (−)-menthol, (+)-isomenthol, (−)nomeol, (R)-2-phenyl glycinol, (S)-2-phenyl glycinol, (R)-4-phenyl-2-oxazolidinone or (S)-4-benzyl-2-oxazolidinone, which chiral group when connected to a carbonyl group can easily be cleaved to the corresponding acid.

Intermediates

a) When preparing the compound of the formula I of the invention an intermediate of the formula IV

wherein Q is hydrogen and A is —OH or —OR^(p), wherein R^(p) is a protective group, e.g. ethyl, or A is a chiral auxiliary group, such as a chiral amine, e.g. (R)-phenylglycinol, or a chiral alcohol such as menthol or a chiral oxazolidinone, such as (S)-4-benzyl-2-oxazolidinone, is particularly useful. It is prepared as described above. Under the same heading its use as intermediate for the preparation of the end compound of the invention is described.

b) When preparing the compound of the formula I of the invention an intermediate of the formula III

wherein X is —OH or a leaving group, such as a sulfonate or a halogen, is particularly useful. It is prepared as described above. Under the same heading its use as intermediate for the preparation of the end product of the invention is described.

Pharmaceutical Preparations

The compound of the invention will normally be administered via the oral, parenteral, intravenous, buccal, rectal, vaginal, transdermal and/or nasal route and/or via inhalation, in the form of pharmaceutical preparations comprising the active ingredient either as a free acid, or a pharmaceutical acceptable organic or inorganic base addition salt, in a pharmaceutically acceptable dosage form. Depending upon the disorder and patient to be treated and the route of administration, the compositions may be administered at varying doses.

The compound of the invention may also be combined with other therapeutic agents which are useful in the treatment of disorders associated with the development and progress of atherosclerosis such as hypertension, hyperlipidemias, dyslipidemias, diabetes and obesity.

Suitable daily doses of the compound of the invention in therapeutical treatment of humans are about 0.005-5 mg/kg body weight, preferably 0.01-0.5 mg/kg body weight.

According to a further aspect of the invention there is thus provided a pharmaceutical formulation including the compound of the invention, or pharmaceutically acceptable derivatives thereof, in optional admixture with pharmaceutically acceptable adjuvants, diluents and/or carriers.

Pharmacological Properties

The present compound of formula (I) will be adapted for prophylaxis and/or treatment of clinical conditions associated with reduced sensitivity to insulin (insulin resistance) and associated metabolic disorders. These clinical conditions will include, but will not be limited to, abdominal obesity, arterial hypertension, hyperinsulinaemia, hyperglycaemia (non insulin dependent diabetes mellitus (NIDDM)) and the dyslipidaemia (plasma lipoprotein disturbances) characteristically appearing with insulin resistance. This dyslipidaemia, also known as the atherogenic lipoprotein profile of phenotype B, is characterised by moderately elevated non-esterified fatty acids, elevated very low density lipoproteins (VLDL) triglycerides, low high density lipoproteins (HDL) cholesterol and the presence of small, dense, low density lipoproteins (LDL). Treatment with the present compound is expected to lower the cardiovascular morbidity and mortality associated with atherosclerosis. These cardiovascular disease conditions include macro-angiophathies causing myocardial infarction, cerebrovascular disease and peripheral arterial insufficiency of the lower extremities. Because of its insulin sensitizing effect the compound of formula (I) is also expected to reduce the progress of clinical conditions associated with chronic hyperglycaemia in diabetes like the micro-angiopathies causing renal disease and retinal damage. Furthermore the compound may be useful in treatment of various conditions outside the cardiovascular system associated with insulin resistance like the polycystic ovarian syndrome. The compound of the invention is a non-toxic insulin sensitizing agent with surprisingly good therapeutic effect and pharmacokinetic properties and without undesirable weight gain.

General Experimental Procedures

¹H NMR and ¹³C NMR measurements were performed on a BRUKER ACP 300 and Varian UNITY plus 400 and 500 spectrometers, operating at ¹H frequencies of 300, 400 and 500 MHz respectively, and at ¹³C frequencies of 75, 100 and 125 MHz respectively.

Unless otherwise stated, chemical shifts are given in ppm with the solvent as internal standard.

EXAMPLE 1 3-{4-[2-(4-tert-Butoxycarbonylaminophenyl)ethoxy]phenyl}-(S)-2-ethoxypropanoic acid a) 3-(4-Benzyloxyphenyl)-2-ethoxyacrylic acid ethyl ester

Tetramethylguanidine (33 g; 0.286 mole) was added to a solution of 4-benzyloxybenzaldehyde (59.1 g; 0.278 mole) and 101.8 g; 0.237 mole) (1,2-dietoxy-2-oxyethyl) (triphenyl) phosphonium chloride in dichloromethane (600 ml) at 0° C. After stirring at room temperature overnight, the solvent was evaporated in vacuo. The residue was dissolved in diethyl ether, insoluble material was filtered off and the filtrate was evaporated. The residue was stirred overnight with sodium bisulfite (saturated water solution) and diethyl ether. The solid material was filtered off, the filtrate was extracted with diethyl ether, dried (magnesium sulfate) and the solvent was evaporated in vacuo. Purification of the crude product by flash chromatography and crystallization in isopropanol gave 66.8 g (yield 86.3%) of 3-(4-benzyloxyphenyl)-2-ethoxyacrylic acid ethyl ester.

¹³C-NMR (125 MHz; CDCl₃): δ14.4, 15.6, 61.0, 67.5, 70.0, 114.8, 124.0, 126.7, 127.5, 128.1, 128.6, 131.7, 136.7, 143.1, 159.2, 165.0.

(b) 2-Ethoxy-3-(4hydroxyphenyl)propanoic acid ethyl ester

3-(4-Benzyloxyphenyl)-2-ethoxyacryhic acid ethyl ester (62 g; 0.19 mole) was hydrogenated in ethyl acetate (400 ml) at atmospheric pressure using Pd/C (10%) as catalyst. The mixture was filtered through celite and evaporated in vacuo to give 45.6 g (yield 100%) of 2-ethoxy-3-(4-hydroxyphenyl)propanoic acid ethyl ester.

¹H-NMR (600 MHz; CDCl₃): δ1.17 (t, 3H, J=7 Hz), 1.23 (t, 3H, J=7 Hz), 2.95 (d, 2H, J=6.6 Hz), 3.35-3.42 (m, 1H), 3.58-3.64 (m, 1H), 4.0 (t, 1H, J=6.6 Hz), 4.17 (q, 2H, J=7 Hz), 5.97 (s, 1 OH), 6.74 (dm, 2H, J=8.5 Hz, unresolved), 7.08 (dm, 2H, J=8.5 Hz, unresolved).

¹³C-NMR (125 MHz; CDCl₃): δ14.0, 14.8, 38.3, 61.0, 66.1, 80.3, 115.1, 128.2, 130.3, 154.8, 173.0.

(c) 4-(2-Hydroxyethyl)phenylcarbamic acid tert-butyl ester

Di-tert-Butyl dicarbonate (7.95 g; 36 mmole) was added to a mixture of p-aminophenethyl alcohol (5 g; 36 mmole) in tetrhydrofuran at 0° C. After stirring at room temperature overnight, the solvent was evaporated in vacuo to give 8 g (yield 94%) of 4-(2-hydroxyethyl)phenylcarbamic acid tert-butyl ester.

¹H-NMR (400 MHz; DMSO-d₆): δ1.5 (s, 9H), 2.65 (dd, 2H), 3.55 (dd, 2H), 4.6 (bs, 1OH), 7.1 (unresolved, 2H), 7.35 (unresolved, 2H), 9.1 (s, 1NH).

¹³C-NMR (100MHz; DMSO-d₆): δ28.3, 38.6, 62.5, 78.9, 118.3, 129.1, 133.2, 136.6, 153.0.

(d) 3-{4-[2-(4-tert-Butoxycarbonylaminophenyl)ethoxy]phenyl}-2-ethoxypropanoic acid ethyl ester

4-(2-Hydroxyethyl)phenylcarbamic acid tert-butyl ester (1.03 g; 4.34 mmole) and 2-ethoxy-3-(4-hydroxyphenyl)propanoic acid ethyl ester (1.03 g; 4.34 mmole) were dissolved in dichloromethane under argon at room temperature. Azodicarbonyl dipiperidine (1.65 g, 6.5 mmole) and thereafter triphenylphosphine (1.37 g; 5.2 mmole) were added. After stirring at room temperature for 6 hours the solvent was evaporated in vacuo. Purification by chromatography on silica gel using heptane ethyl acetate (2:1) as eluant gave 1.78 g (yield 89%) of 3-{4-[2-(4-tert-butoxycarbonylaminophenyl)ethoxy]-phenyl}-2-ethoxypropanoic acid ethyl ester.

¹H-NMR (400 MHz; CDCl₃): δ1.17 (t, 3H, J=7 Hz), 1.23 (t, 3H, J=7 Hz), 1.53 (s, 9H), 2.94-2.97 (m, 2H), 3.03 (t, 2H, J=7.1 Hz), 3.31-3.40 (m, 1H), 3.56-3.65 (m 1H), 3.95-4.0 (m, 1H), 4.11 (t, 2H, J=7.1 Hz), 4.17 (q, 2H, J=7 Hz), 6.60 (s, 1NH), 6.81 (dm, 2H, J=8.3 Hz, unresolved), 7.15 (dm, 2H, J=8.3 Hz, unresolved), 7.20 (dm, 2H, J=8.3 Hz, unresolved), 7.31 (dm, 2H, J=8.3 Hz, unresolved).

¹³C-NMR (100 MHz; CDCl₃): δ14.1, 15.0, 28.3, 35.0, 38.4, 60.7, 66.1, 68.6, 80.26, 80.32, 114.3, 118.7, 128.2, 129.4, 130.3, 132.8, 136.7, 152.8, 157.5, 172.4.

(e) 3-{4-[2-(4-tert-Butoxycarbonylaminophenyl)-ethoxy]phenyl}-2-ethoxypropanoic acid

Lithium hydroxide hydrate (77 mg; 1.85 mmole) in water (5.5 ml) was slowly added to a solution of 3-{4-[2-(4-tert-butoxycaxbonylaminophenyl)ethoxy]phenyl}-2-ethoxypropanoic acid ethyl ester (0.77 g; 1.68 mmole) in tetrahydrofuran (7.6 ml). After stirring at room temperature for 4 hours the reaction mixture was kept in a freezer for 4 days. Tetrahydrofuran was removed by evaporation in vacuo. More water was added and the mixture was acidified with hydrochloric acid to pH 1. The product was extracted with ethyl acetate, washed twice with water, dried (sodium sulfate), filtered and the solvent was evaporated in vacuo to give 0.716 g of 3-{4-[2-(4-tert-butoxycarbonylamiinophenyl)-ethoxy]phenyl}-2-ethoxypropanoic acid.

¹H-NMR (400 MHz; CDCl₃): δ1.18 (t, 3H, J=7 Hz), 1.54 (s, 9H), 2.93-3.10 (m, 4H), 3.36-3.45 (m, 1H), 3.60-3.69 (m, 1H), 4.02-4.07 (m, 1H), 4.12 (t, 2H, J=7 Hz), 6.83 (dm, 2H, J=8.8 Hz, unresolved), 7.15-7.23 (m, 4H), 7.27-7.34 (m, 2H), 10.28 (bs, 1H).

¹³C-NMR (100 MHZ; CDCl₃): δ15.0, 28.3, 35.2, 38.0, 66.7, 68.8, 79.9, 80.7, 114.6, 119.1, 129.0, 129.4, 130.4, 133.1, 136.8, 153.2, 157.8, 175.3.

(f) 3-{4-[2-(4-tert-Butoxycarbonylaminophenyl)ethoxy]phenyl}-(S)-2-ethoxypropanoic acid

The enantiomers of 3-{4-[2-(4-tert-butoxycarbonylaminophenyl)ethoxy]phenyl}-2-ethoxypropanoic acid were separated with preparative HPLC (Chiralpak AD 250×20 mm) using heptane, isopropanol and trifluoroacetic acid (80/20/0.5) as mobil phase giving 3-{4-[2-(4-tert-butoxycarbonylaminophenyl)ethoxy]phenyl}-(S)-2-ethoxypropanoic acid as a pure enantiomer.

¹H-NMR (600 MHz; CDCl₃): δ1.17 (t, 3H), 1.51 (s, 9H), 2.93 (dd, 1H), 3.02 (t, 2H), 3.07 (dd, 1H), 3.42-3.47 (m, 1H), 3.55-3.6 (m, 1H), 4.04 (dd, 1H), 4.1 (t, 2H), 6.5 (bs, 1H), 6.8 (d, 2H), 7.13 (d, 2H), 7.19 (d, 2H), 7.28 (d, 2H).

¹³C-NMR (100 MHz; CD₃OD): δ15.3, 28.7, 36.1, 39.3, 67.1, 69.9, 80.7, 81.3, 115.4, 120.0, 130.3, 130.7, 131.4, 134.2, 138.8, 155.4, 159.1, 176.0.

EXAMPLE 2 3-{4-[2-(4-tert-Butoxycarbonylaminophenyl)ethoxy]phenyl}-(S)-2-ethoxypropanoic acid a) 3-(4-Benzyloxyphenyl)-2-ethoxypropanoic acid ethyl ester

3-(4-Benzyloxyphenyl)-2-ethoxyacrylic acid ethyl ester (described in Example 1a) (0.5 g; 1.5 mole) was hydrogenated at atmospheric pressure using rhodium on charcoal as catalyst (5%, 50 mg) in methanol (20 ml). The crude product was purified by chromatography using heptane:ethyl acetate (5:1) as eluent to give 50 mg (yield 10%) of 3-(4-benzyloxyphenyl)-2-ethoxypropanoic acid ethyl ester.

¹H NMR (300 MHz; CDCl₃): δ7.47-7.30 (m, 5H), 7.17 (d, J=8.8, 2H), 6.91 (d, J=8.8 Hz, 2H), 5.06 (s, 2H), 4.17 (q, J=7.2 Hz, 2H), 3.98 (t, J=6.6 Hz, 1H), 3.61 (dq, J=8.9 and 6.8 Hz, 1H), 3.36 (dq, J=8.9 and 6.8 Hz, 1H), 2.97 (d, J=6.6 Hz, 2H), 1.22 (t, J=7.2 Hz, 2H), 1.18 (t, J=6.8 Hz, 3H).

¹³C NMR (75 MHz; CDCl₃): δ172.6, 157.6, 137.1, 130.4, 129.5, 128.6, 127.9, 127.5, 114.6, 80.4, 70.0, 66.2, 60.8, 38.5, 15.1, 14.2.

b) 3-(4-Benzyloxyphenyl)-2-ethoxypropanoic acid

Lithium hydroxide hydrate (7.4 g; 177 mmole) dissolved in water (150 ml) was added to a solution of 3-(4-benzyloxyphenyl)-2-ethoxypropanoic acid ethyl ester (23.25 g; 70.8 mmole) in dioxane (150 ml). After stirring at room temperature over night dioxane was evaporated in vacuo, water was added and the mixture was washed with diethyl ether. The water phase was acidified with hydrochloric acid (1 M) and the crude product was extracted with ethyl acetate, washed with water and brine, dried and the solvent was evaporated in vacuo to give 21.1 g (yield 99.2%) of 3-(4benzyloxyphenyl)-2-ethoxypropanoic acid.

¹H NMR (300 MHz; CDCl₃): δ1.15 (t, 3H), 2.9-3.1 (m, 2H), 3.35-3.45 (m, 1H), 3.6-3.7 (m, 1H), 3.95-3.41 (m, 1H), 5.05 (s, 2H), 6.95 (d, 2H), 7.2 (d, 2H), 7.25-7.5 (m, 5H).

¹³C NMR (75 MHz; CDCl₃): δ15.0, 38.1, 66.6, 70.0, 79.9, 114.7, 127.5, 128.0, 128.6, 129.3, 130.5, 137.1, 157.7, 176.3.

c) 3-(4-Benzyloxyphenyl)-(S)-2-ethoxy-N-(2-hydroxy-(R)-1-phenylethylpropanoic amide

EDC (2.03 g; 10.61 mmole), diisopropylethylamine (1.84 ml, 10.61 mmole) and HOBt×H₂O (1.43 g; 10.61 mmole) were added to a solution of 3-(4-benzyloxyphenyl)-2-ethoxypropanoic acid (2.92 g, 9.74 mmole) in dry dichloromethane (30 ml) on an ice-bath. After 30 minutes the ice-bath was removed and (R)-phenylglycinol (1.46 g, 10.61 mmole) was added. After stirring at room temperature overnight ethyl acetate (100 ml) was added and the solution was washed with potassium hydrogensulfate (1 M), saturated sodium bicarbonate solution, sodium carbonate solution and brine. The organic phase was dried (sodium sulfate), filtered and the solvent was evaporated in vacuo. The crude product was purified by chromatography on silica gel using ethyl acetate:heptane to give 1.5 g (yield 37%) of 3-(4-benzyloxyphenyl)-(S)-2-ethoxy-N-(2-hydroxy-(R)-1-phenylethyl)propanoic amide and 1.25 g (yield 31%) of 3-(4-benzyloxyphenyl)-(R)-2-ethoxy-N-(2-hydroxy-(R)-1-phenylethyl)propanoic amide.

¹H NMR (400 MHz; CDCl₃): δ7.43-7.27 (m, 8H), 7.22 (d, J=8.3 Hz, 4H), 7.13 (d, NH, J=7.8 Hz, 1H), 6.96 (d, J=8.3 Hz, 1H), 5.08 (s, 2H), 5.01 (m, 1H), 3.99 (dd, J=6.8 and 3.9 Hz, 1H), 3.69 (m, 2H), 3.50 (q, J=6.8 Hz, 2H), 3.15 (dd, J=14.2 and 3.9 Hz, 1H), 2.97 (dd, J=14.2 and 6.8 Hz, 1H), 2.94 (m, OH, 1H), 1.16 (t, J=6.8 Hz, 3H).

¹³C NMR (100 MHz; CDCl₃): δ172.3, 157.5, 138.9, 137.0, 130.7, 129.4, 128.6, 128.4, 127.7, 127.6, 127.3, 126.5, 114.4, 81.0, 69.8, 66.3, 66.0, 55.3, 37.8, 15.1.

d) 3-(4-Benzyloxyphenyl)-(S)-2-ethoxypropanoic acid

3-(4-Benzyloxyphenyl)-(S)-2-ethoxy-N-(2-hydroxy-(R)-1-phenylethyl)propanoic amide (8.9 g; 21.22 in mole) was hydrolyzed with concentrated sulfuric acid (27 ml) in water (104 ml) and dioxane (104 ml) at 90° C. for 5 hours. The reaction mixture was poured onto water (220 ml) and extracted with ethyl acetate. The organic phase was washed with brine, dried (sodium sulfate) and the solvent was evaporated in vacuo to give 6.85 g of a mixture of 3-(4-benzyloxyphenyl)-2-(S)-ethoxypropanoic acid and (S)-2-ethoxy-3-(4-hydroxyphenyl)-propanoic acid, which was used without further purification.

¹H NMR (400 MHz; CDCl₃): δ7.47-7.30 (m, 5H), 7.19 (d, J=8.8, 2H), 6.93 (d, J=8.8 Hz, 2H), 5.10 (s, 2H), 4.06 (dd, J=7.8 and 4.4 Hz, 1H), 3.64 (dq, J=9.8 and 6.8 Hz, 1H), 3.44 (dq, J=9.8 and 6.8 Hz, 1H), 3.09 (dd, J=14.2 and 4.4 Hz, 1H), 2.98 (dd, J=14.2 and 7.8 Hz, 1H), 1.19 (t, J=6.8 Hz, 3H).

e) 3-(4-Benzyloxyphenyl)-(S)-2-ethoxypropanoic acid ethyl ester

Hydrogen chloride (g) was bubbled through a solution of 3-(4-benzyloxyphenyl)-2-(S)-ethoxypropanoic acid (6.85 g) in ethanol (400 ml). Thionyl chloride (2 ml, 27.4 mmole) was slowly added and the reaction mixture was refluxed for 2 hours. The solvent was evaporated in vacuo to give 8 g of a mixture of 3-(4-benzyloxyphenyl)-(S)-2-ethoxypropanoic acid ethyl ester and (S)-2-ethoxy-3-(4-hydroxyphenyl)propanoic acid ethyl ester which was used without further purification.

¹H NMR (300 MHz; CDCl₃): δ7.47-7.30 (m, 5H), 7.17 (d, J=8.8, 2H), 6.91 (d, J=8.8 Hz, 2H), 5.06 (s, 2H), 4.17 (q, J=7.2 Hz, 2H), 3.98 (t, J=6.6 Hz, 1H), 3.61 (dq, J=8.9 and 6.8 Hz, 1H), 3.36 (dq, J=8.9 and 6.8 Hz, 1H), 2.97 (d, J=6.6 Hz, 2H), 1.22 (t, J=7.2 Hz, 3H), 1.18 (t, J=6.8 Hz, 3H).

¹³C NMR (75 MHz; CDCl₃): δ172.6, 157.6, 137.1, 130.4, 129.5, 128.6, 127.9, 127.5, 114.6, 80.4, 70.0, 66.2, 60.8, 38.5, 15.1, 14.2.

f) (S)-2-Ethoxy-3-(4-hydroxyphenyl)propanoic acid ethyl ester

3-(4-Benzyloxyphenyl)-(S)-2-ethoxypropanoic acid ethyl ester was hydrogenated at atmospheric pressure for 2 hours in ethyl acetate using Pd/C as catalyst. Purification by chromatography on silica gel using toluene:ethyl acetate as eluant gave 3.83 g (yield in 3 steps 76%) of (S)-2-ethoxy-3-(4-hydroxyphenyl)propanoic acid ethyl ester.

¹H-NMR (400 MHz; CDCl₃): δ1.18 (t, 3H, J=6.8 Hz), 1.24 (t, 3H, J=7 Hz), 2.96 (d, 2H, J=6.5 Hz), 3.34-3.43 (m, 1H), 3.57-3.66 (m, 1H), 4.00 (t, 1H, 6.5 Hz), 4.18 (q, 2H, J=7 Hz), 5.30 (s, 1 OH), 6.74 (dm, 2H, J=8.5 Hz, unresolved), 7.10 (dm, 2H, J=8.5 Hz, unresolved).

¹³C-NMR (100 MHz; CDCl₃): δ14.2, 15.0, 38.4, 60.9, 66.2, 80.4, 115.1, 129.0, 130.5, 154.5, 172.7.

g) 2-[4-(tert-Butoxycarbonylamino)phenyl]ethylmethanesulfonate

4-(2-Hydroxyethyl)phenylcarbamic acid tert-butylester (described in Example 1 (c)) (2.46 g; 10.38 mmole) was dissolved in dichloromethane (21 ml). Triethylamine (2.17 ml; 15.6 mmole) was added and the mixture was stirred for 20 min and then cooled on an ice-bath. Methanesulfonyl chloride (1.25 g, 10.9 mmole) was added slowly. The reaction mixture was stirred for 3.5 hours and the formed precipitate was filtered off. The filtrate was evaporated and the residue redissolved in ethyl acetate. A new precipitate was formed and filtered off and the filtrate evaporated. Chromatography on silica using heptane: ethyl acetate (2:1, 1:1) gave 3 g (100% yield) of 2-[4-(tert-butoxycarbonylamino)phenyl]-ethylmethanesulfonate

¹H-NMR (400 MHz; CDCl₃): δ1.52 (s, 9H), 2.87 (s, 3H), 3.01 (t, 2H), 4.39 (t, 2H), 7.16 (d, 2H, J=8.45 Hz), 6.45 (bs, 1H), 7.33 (d, 2H, J=8.45 Hz)

¹³C-NMR (100 MHz; CDCl₃: δ28.2, 34.8, 37.1, 70.2, 80.3, 118.6, 129.2, 130.5, 137.3, 152.6.

h) 3-{4-[2-(4-tert-Butoxycarbonylaminophenyl)ethoxy]phenyl}-(S)-2-ethoxypropanoic acid ethyl ester

2-[4-(tert-Butoxycarbonylamino)phenyl]ethylmethanesulfonate (52.9 g; 0.168 mmole), (S)-2-ethoxy-3-(4-hydroxyphenyl)propanoic acid ethyl ester (40 g; 0.168 mmole) and potassium carbonate (69.5 g; 0.503 mmole) were mixed in acetonitrile (1200 ml) and refluxed overnight. Another portion of 2-[4-(tert-butoxycarbonylamino)phenyl]-ethylmethanesulfonate (2.5 g; 7.9 mmole) was added. The reaction mixture was refluxed for 8 more hours then filtered. Evaporation of the filtrate gave 76.6 g 3-{4-[2-(4-tert-butoxycarbonylaminophenyl)ethoxy]phenyl}-(S)-2-ethoxypropanoic acid ethyl ester.

This batch of 3-{4-[2-(4-tert-butoxycarbonylaminophenyl)ethoxy]phenyl}-(S)-2-ethoxypropanoic acid ethyl ester (76.6 g) was combined with another batch of 3-{4-[2-(4-tert-butoxycarbonylaminophenyl)ethoxy]phenyl}-(S)-2-ethoxypropanoic acid ethyl ester (74.1 g) and flash chromatographed on silica using first toluene and then methanol as eluant. This gave a main fraction of 80 g ester which was split in two portions of 40 g each and chromatographed on silica using toluene: ethyl acetate (2-5%) as eluant. This procedure gave 69.9 g of pure 3-{4-[2-(4-tert-butoxycarbonylaminophenyl)ethoxy]phenyl}-(S)-2-ethoxypropanoic acid ethyl ester.

¹H-NMR (400 MHz; CDCl₃): δ1.16 (t, 3H), 1.22 (t, 3H), 1.51 (s, 9H), 2.94 (d, 2H), 3.02 (t, 2H), 3.31-3.38 (m, 1H), 3.55-3.63 (m, 1H), 3.95 (t, 1H), 4.10 (t, 2H), 4.16 (q, 2H), 6.45 (bs, 1H), 6.8 (d, 2H), 7.13 (d, 2H), 7.19 (d, 2H), 7.29 (d, 2H).

i) 3-{4-[2-(4-tert-Butoxycarbonylaminophenyl)ethoxy]phenyl}-(S)-2-ethoxypropanoic acid

3-{4-[-(tert-Butoxycarbonylaminophenyl)ethoxy]phenyl}-(S)-2-ethoxypropanoic acid ethyl ester (27 g; 0.06 mmole) was dissolved in TBF (250 ml), and water (250 ml) was added during followed by addition of lithium hydroxide hydrate (3.75 g; 0.089 mmole) dissolved in a small amount of water. The reaction mixture was stirred at room temperature overnight and then concentrated by evaporation The residue was washed once with ethyl acetate. The water phase was acidified upon cooling with hydrochloric acid (2M) and extracted with ethyl acetate. The organic phase was washed with brine dried with magnesium sulfate and evaporated. The residue was redissolved in dichloromethane and chromatography on silica using a gradient system of dichloromethane: methanol (0-100%) gave 21.3 g (83% yield) 3-{4-[2-(4-tert-butoxycarbonylamiinophenyl)ethoxy]phenyl}-(S)-2-ethoxypropanoic acid.

¹H-NMR (600 MHz; CDCl₃: δ1.17 (t, 3H), 1.51 (s, 9H), 2.93 (dd, 1H), 3.02 (t, 2H), 3.07 (dd, 1H), 3.42-3.47 (m, 1H), 3.55-3.6 (m, 1H), 4.04 (dd, 1H), 4.1 (t, 2H), 6.5 (bs, 1H), 6.8 (d, 2H), 7.13 (d, 2H), 7.19 (d, 2H), 7.28 (d, 2H).

¹³C-NMR (100 MHz; CD₃OD): δ15.3, 28.7, 36.1, 39.3, 67.1, 69.9, 80.7, 81.3, 115.4, 120.0, 130.3, 130.7, 131.4, 134.2, 138.8, 155.4, 159.1, 176.0.

Biological Activity

The biological activity of the compound of the invention was tested in obese diabetic mice of the Umeå ob/ob strain. Groups of mice received the test compound by gavage once daily for 7 days. On the last day of the experiment the animals were anesthetized 2 h after dose in a non-fed state and blood was collected from an incised artery. Plasma was analyzed for concentration of glucose, insulin and triglycerides. A group of untreated obese diabetic mice of the same age served as control. The weights of the mice were measured before and after the experiment and the obtained weight gains were compared to the weight gains of the control animals. The individual values for glucose, insulin and triglyceride levels of the mice from the test group were expressed as the percentage rage of the corresponding values from the control group. The desired “therapeutic effect” was calculated as the average percent reduction of the three variables glucose, insulin and triglycerides below the levels in the control animals. The therapeutic effect of the tested compounds according to the invention was compared to the same effect in the prior art compound troglitazone, administrered by gavage in the oral dose of 100 μmol/kg for 7 days.

The superior effects of the tested compound according to the invention compared to that of troglitazone when given in the same oral dose demonstrate the increased potency and efficiacy of the claimed compound.

Abbreviations NIDDM non insulin dependent diabetes mellitus VLDL very low density lipoproteins HDL high density lipoproteins IRS insulin resistance syndrom PPAR peroxisome proliferator activated receptor DEAD diethyl azodicarboxylate ADDP azodicarbonyl dipiperidine EDC 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide EDCxHCl 1-(3-diethylaminopropyl)-3-ethylcarbodiimide hydrochloride DCC dicyclohexylcarbodiimide HBTU O-benzotriazol-1-yl-N,N,N′,N′-tetramethyluronium hexafluorophosphate TBTU O-benzotriazol-1-yl-N,N,N′,N′-tetramethyluronium tetrafluoroborate PyBop benzotriazole-1-yl-oxy-tris-pyrolidino-phosphonium hexafluorophosphate DMF dimethylformamide DMAP 4-dimethylaminopyridine TEA triethylamine DiPEA diisopropylethylamine BINAP 2,2′-bis(diphenylphosphino)-1,1′-binaphtyl COD cyclooctadiene LDA lithium diisopropylamide LHMDS lithium hexamethyldisilylamine TLC thin layer chromatography THF tetrahydrofuran Pd/C palladium on charcoal HOBt x H2O 1-hydroxybenzotriazole-hydrate m multiplet t triplet s singlet d doublet q quartet qvint quintet br broad dm multiplet of doublet rac racemate 

What is claimed is:
 1. A compound of formula I

or a pharmaceutically acceptable salt, solvate or crystalline form thereof.
 2. A process for the preparation of a compound according to claim 1, which comprises a) converting a compound of formula II

 wherein A is a chiral auxiliary group or —OR^(p), wherein R^(p) is a protective group, or b) reacting a compound of formula III

 with a compound of formula IV

 in which formulas A is —OH, a chiral auxiliary group or the group —OR^(p), wherein R^(p) is a protective group, X is —OH or a leaving group and Q is H, optionally followed by hydrolyzing the obtained compound, or c) diastereoisomerically separating a compound of formula V

 wherein Q is —Ch₂Ch₂Ph-4-NHCOO^(t)Bu and A is a chiral auxiliary group, followed by hydrolyzing the obtained compound, or d) enantiomerically separating a compound of formula V

 wherein Q is —Ch₂Ch₂Ph-4-NHCOO^(t)Bu and A is —OH or —OR^(p), wherein R^(p) is a protective group, optionally followed by hydrolyzing the obtained compound, or e) asymmetrically reducing a compound of formula VII

 wherein Q is —Ch₂Ch₂Ph-4-NHCOO^(t)Bu and A is —OH, a chiral auxiliary group or the group —OR^(p), wherein R^(p) is protective group, optionally followed by hydrolyzing the obtained compound, or f) alkylating a compound of formula XII

 wherein Q is —Ch₂Ch₂Ph-4-NHCOO^(t)Bu and A is —OH, a chiral auxiliary group or the group —OR^(p), wherein R^(p) is a protective group, optionally followed by hydrolyzing the obtained compound, or g) reacting a compound of formula XV

 with a compound of formula IX

 in which formulas X is a leaving group, Q is —Ch₂Ch₂Ph-4-NHCOO^(t)Bu and A is a chiral auxiliary group used to induce chirality in the compound, followed by hydrolyzing the obtained compound, or h) resolving a racemate of formula I^(rac)

whereafter the compound obtained according to any of methods a)-h) is optionally converted to a pharmaceutically acceptable salt and/or a solvate thereof.
 3. A pharmaceutical formulation containing a compound according to claim 1 as active ingredient optionally together with a pharmaceutically acceptable carrier, adjuvant and/or diluent.
 4. A method for the prophylaxis and/or treatment of clinical conditions associated with insulin resistance wherein a therapeutically active amount of a compound according to claim 1 is administered to a mammal in the need of such prophylaxis and/or treatment.
 5. A method according to claim 4 wherein the clinical condition is dyslipidaemia.
 6. A method according to claim 4 wherein the clinical condition is hyperglycaemia in non insulin dependent diabetes mellitus.
 7. A pharmaceutical formulation for the prophylaxis and/or treatment of clinical conditions associated with insulin resistance wherein the active ingredient is a compound according to claim
 1. 